400hp is possible.
BUT you need to do a lot of research into whether it will achieve what you want. A number of people have fitted SC kits and hated what their car became.
As above, go read up over on the US forum. Lots of advice there.
Speak to Tarmac Sportz (a trader here) and see what price he can do for you. Bearing in mind all the ancillary mods you will need to do (Fuel return system, uprated fuel pump, injectors, uprated clutch, exhaust, oil cooler, uprated brakes....)